/Engine/Source/Runtime/SlateCore/Public/Widgets/SWidget.h
The index of the child that is under the specified position
static int32 FindChildUnderPosition ( const [FArrangedChildren](API\Runtime\SlateCore\Layout\FArrangedChildren) & Children, const [UE::Slate::FDeprecateVector2DParameter](API\Runtime\SlateCore\Types\FDeprecateVector2DParameter) & ArrangedSpacePosition )